src/client.js: Fix incorrect roomId reference in VoIP glare code
src/client.js: Fix incorrect roomId reference in VoIP glare code

MatrixCall has a roomId property, but not a room_id property.

krombel/matrix-js-sdk,matrix-org/matrix-js-sdk,matrix-org/matrix-js-sdk,krombel/matrix-js-sdk,matrix-org/matrix-js-sdk,matrix-org/matrix-js-sdk,krombel/matrix-js-sdk